Regulations may require that certain users should not call other users. For example, Sarbanes-Oxley (SOX) includes a set of requirements where a user from the auditing side of a company is not allowed to place a phone call or have an instant messaging (IM) session with someone from the business consulting side of the company. Conventionally, telephony and IM systems do not enforce which caller or IM client can communicate with which callee/buddy.
Applications may be modified to route calls through a gateway or proxy. In this case, the gateway or proxy address is physically configured in a user's client, such as a user's IM client or VoIP telephone. Accordingly, the application is manually configured to send all traffic through the gateway or proxy, which can then monitor the communications. This approach, however, requires modifying the application on each user's desktop. This is time consuming and changes the application's normal behavior in sending communications to other users. Further, when the applications or gateways are changed to different vendors, the modification of the applications has to be performed again.